Clinical performance of primary HPV screening cut-off for colposcopy referrals in HPV-vaccinated cohort: Observational study.

OBJECTIVE: To understand the effect of changing from cytology-based to primary HPV screening on the positive predictive value (PPV) of colposcopy referrals for cervical intraepithelial neoplasia (CIN) in a cohort offered HPV vaccination. DESIGN: Retrospective pre/post observational cohort study. SETTING: Scotland. POPULATION OR SAMPLE: 2193 women referred to colposcopy between September 2019 and February 2020 from cytology-based screening and between September 2020 and February 2021 from primary high-risk HPV (hrHPV) screening. METHODS: Calculating positive predictive values (PPVs) for two cohorts of women; one having liquid-based cytology screening and the other, the subsequent hrHPV cervical screening as a pre/post observational study. MAIN OUTCOME MEASURES: Positive predictive values of LBC and hrHPV cut-offs for colposcopy referral for CIN at colposcopy. RESULTS: Three papers fitted our criteria; these reported results only for cytology-based screening. The PPV was lower for women in HPV-vaccinated cohorts indicating a lower prevalence of disease. Vaccination under the age of 17 had the lowest PPV reported. Scottish colposcopy data concerning hrHPV and cytology showed a non-significant difference between PPV (17.5%, 95% CI 14.3-20.7, and 20.6, 95% CI 16.7-24.5, respectively) for referrals with a cut-off of low grade dyskaryosis (LGD); both met the standard set of 8-25%. The hrHPV PPV (66.7, 95% CI 56.8-76.6) was comparable to cytology (64.1, 95% CI 55.8-72.4) for referrals with a cut-off of high grade dyskaryosis (HGD) but neither met the standard set of 77-92%. CONCLUSIONS: Current literature only provides PPVs for LBC and, overall, the vaccinated cohort had lower PPVs. Only LG dyskaryosis met PHE criteria. The PPV for HPV-vaccinated women undergoing either LBC or HR-HPV screening were not statistically different. However, similar to papers in the current literature, HG dyskaryosis (HGD) PPVs of both techniques did not meet the PHE threshold of 76.6-91.6% outlined in the cervical standards data report.

Insights into the Antibacterial Mechanism of Action of Chelating Agents by Selective Deprivation of Iron, Manganese, and Zinc.

Bacterial growth and proliferation can be restricted by limiting the availability of metal ions in their environment. Humans sequester iron, manganese, and zinc to help prevent infection by pathogens, a system termed nutritional immunity. Commercially used chelants have high binding affinities with a variety of metal ions, which may lead to antibacterial properties that mimic these innate immune processes. However, the modes of action of many of these chelating agents in bacterial growth inhibition and their selectivity in metal deprivation in cellulo remain ill-defined. We address this shortcoming by examining the effect of 11 chelators on Escherichia coli growth and their impact on the cellular concentration of five metals. The following four distinct effects were uncovered: (i) no apparent alteration in metal composition, (ii) depletion of manganese alongside reductions in iron and zinc levels, (iii) reduced zinc levels with a modest reduction in manganese, and (iv) reduced iron levels coupled with elevated manganese. These effects do not correlate with the absolute known chelant metal ion affinities in solution; however, for at least five chelators for which key data are available, they can be explained by differences in the relative affinity of chelants for each metal ion. The results reveal significant insights into the mechanism of growth inhibition by chelants, highlighting their potential as antibacterials and as tools to probe how bacteria tolerate selective metal deprivation. IMPORTANCE Chelating agents are widely used in industry and consumer goods to control metal availability, with bacterial growth restriction as a secondary benefit for preservation. However, the antibacterial mechanism of action of chelants is largely unknown, particularly with respect to the impact on cellular metal concentrations. The work presented here uncovers distinct metal starvation effects imposed by different chelants on the model Gram-negative bacterium Escherichia coli. The chelators were studied both individually and in pairs, with the majority producing synergistic effects in combinations that maximize antibacterial hostility. The judicious selection of chelants based on contrasting cellular effects should enable reductions in the quantities of chelant required in numerous commercial products and presents opportunities to replace problematic chemistries with biodegradable alternatives.

On the Antibacterial Activity of Azacarboxylate Ligands: Lowered Metal Ion Affinities for Bis-amide Derivatives of EDTA do not mean Reduced Activity.

EDTA is widely used as an inhibitor of bacterial growth, affecting the uptake and control of metal ions by microorganisms. We describe the synthesis and characterisation of two symmetrical bis-amide derivatives of EDTA, featuring glycyl or pyridyl substituents: AmGly2 and AmPy2 . Metal ion affinities (logK) have been evaluated for a range of metals (Mg2+ , Ca2+ , Fe3+ , Mn2+ , Zn2+ ), revealing less avid binding compared to EDTA. The solid-state structures of AmGly2 and of its Mg2+ complex have been determined crystallographically. The latter shows an unusual 7-coordinate, capped octahedral Mg2+ centre. The antibacterial activities of the two ligands and of EDTA have been evaluated against a range of health-relevant bacterial species, three Gram negative (Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae) and a Gram positive (Staphylococcus aureus). The AmPy2 ligand is the only one that displays a significant inhibitory effect against K. pneumoniae, but is less effective against the other organisms. AmGly2 exhibits a more powerful inhibitory effect against E. coli at lower concentrations than EDTA (<3 mm) or AmPy2 , but loses its efficacy at higher concentrations. The growth inhibition of EDTA and AmGly2 on mutant E. coli strains with defects in outer-membrane lipopolysaccharide (LPS) structures has been assessed to provide insight into the unexpected behaviour. Taken together, the results contradict the assumption of a simple link between metal ion affinity and antimicrobial efficacy.

Effects of bovine colostrum supplementation on upper respiratory illness in active males.

Bovine colostrum (COL) has been advocated as a nutritional countermeasure to exercise-induced immune dysfunction and increased risk of upper respiratory illness (URI) in athletic populations, however, the mechanisms remain unclear. During winter months, under double-blind procedures, 53 males (mean training load±SD, 50.5±28.9 MET-hweek(-1)) were randomized to daily supplementation of 20g of COL (N=25) or an isoenergetic/isomacronutrient placebo (PLA) (N=28) for 12weeks. Venous blood was collected at baseline and at 12weeks and unstimulated saliva samples at 4 weeks intervals. There was a significantly lower proportion of URI days and number of URI episodes with COL compared to PLA over the 12weeks (p<0.05). There was no effect of COL on in vitro neutrophil oxidative burst, salivary secretory IgA or salivary antimicrobial peptides (p>0.05), which does not support previously suggested mechanisms. In a subset of participants (COL=14, PLA=17), real-time quantitative PCR, targeting the 16S rRNA gene showed there was an increase in salivary bacterial load over the 12 weeks period with PLA (p<0.05) which was not as evident with COL. Discriminant function analysis of outputs received from serum metabolomics showed changes across time but not between groups. This is the first study to demonstrate that COL limits the increased salivary bacterial load in physically active males during the winter months which may provide a novel mechanism of immune-modulation with COL and a relevant marker of in vivo (innate) immunity and risk of URI.